[ns] Urgent - SplitObject Error !!

[Madan]

Hi all, 

I am attempting to set up a simulate a Wireless Network 
(Directional Antenna With Multiple Interfaces). I am running my program on Linux 9.0 with NS-2.26. 

While executing the code I get the error 

 (_o21 cmd line 1)
    invoked from within
"_o21 cmd arptable"
    invoked from within
"catch "$self cmd $args" ret"
    (procedure "_o21" line 2)
    (SplitObject unknown line 2)
    invoked from within
"[$node_(0) set ll_(0) ] arptable"
    invoked from within
"set arptbl [[$node_(0) set ll_(0) ] arptable]"
    (file "2node.tcl" line 84)

Please respond...
Madan